Printing unit

ABSTRACT

A character printing unit having an inertia driven hammer assembly, the unit which including a rotating non-circular shaft controlled by a clutch and a brake, the clutch, when energized coupling a drive motor to the shaft. The shaft is adapted to drive a high speed rotary inertia element through a gear mounted on the shaft, the inertia element driving the hammer to print a character upon braking of the shaft element.

United States Patent Moss 2 [451 Dec. 5, 1972 [54] PRINTING UNIT [72]Inventor: James R. Moss, Mt. Clemens, Mich.

[73] Assignee: Nortron, lnc., Ann Arbor, Mich.

[221 Filed: April 14, 1971 [21] Appl. No.: 134,070

Related US. Application Data [63] Continuation of Ser. No. 808,821,March 20, 1969,

abandoned.

[52] U.S.Cl ..l0l/93 C, 74/1255, 197/53 [51] Int.Cl ..B41j7/44,B41j23/10[58] FieldofSearch ..101/93RC;178/34;74/l12, 74/125.5

[56] References Cited UNITED STATES PATENTS 1,971,858 8/1934 Knutsen..10l/93X 75km? r/x112 j}? flmydzmlr.

i (Pf/1x1? 2,895,411 7/1959 Demer et al..... ..l0l/93 2,897,752 8/1959Malmros et aL. ...10l/93 3,128,694 4/1964 Kittler ...101/93 3,128,6964/1964 Hoffman ..101/93 3,185,283 5/1965 Spitsbergen et a1. ..10l/93 X3,232,402 2/1966 Koenen et al ..74/l25.5 X

Primary Examiner--Clyde l. Coughenour Attorney-Harness, Dickey andPierce [5 7] ABSTRACT 17 Claims, 6 Drawing Figures PRINTING UNIT Thisapplication is a continuation of Ser. No. 808,821 filed Mar. 20, 1969,now abandoned.

BACKGROUND AND SUMMARY OF THE DEVELOPMENT which utilizes a'high speedinertia member to actuate lo the hammer of the unit upon correlation ofthe position of the character mounting assembly with the platen. Whilethe following specification will be couched particularly in terms of aprinting unit, it is to be understood that the invention is equallyapplicable to other character recording or coded information units, suchas a punch unit, having a character recording mechanism and a recordingand nonrecording cycle.

In the prior art character printing systems it has been the practice toactuate the print mechanism by means of springs, solenoids or other likedevices which generally start from a rest position and are actuated orenergized to impart mechanical energy to the hammer. These systems,while being satisfactory for low speed operation, are not particularlyadapted to the accuracy FIG. 2 is a side view of the character printingunit of FIG. 1;-

FIG. 3 is a perspective view illustrating certain principles of thepresent invention, including a portion of the control circuit for thecharacter printing unit;

FIG. 4 is a cross sectional view on a plane through the main shaft ofthe character printing unit and particularly illustrating the details ofthe drive and inertia gear element;

FIG. 5 is a cross sectional view illustrating the details of onepreferred form of 90 drive for driving the character disc of a characterprinting unit; and

FIG. 6 is a graph illustrating a shaft revolutions versus timerelationship for a typical printing cycle.

Referring now to the drawings, particularly to FIGS. 1 and 2 thereof,there is illustrated one form of character printing unit 10incorporating the principles of the present invention. The unit 10 isgenerally of the required in high speed printing operation, do not havethe required quick recovery of the hammer and generally have thecharacteristic that the inertia of the system works against the desiredresult of actuating the hammer.

Accordingly, it is one object of the present invention to provide animproved dynamic energy producing assembly for use in connection with acharacter recording unit.

It is another object of the present invention to provide an improvedenergy generating apparatus for a character recording unit whicheliminates springs and solenoids from the energy transmitting assemblyfor the mechanism of a character recording unit.

It is a further object of the present invention to provide an improvedcharacter print assembly which incorporates a high inertia rotatingdevice to impart energy to the print hammer when it is desired to printa character. I

It is a further object of the present invention to pro vide an improvedimpulse system for a print hammer which incorporates the feature of aquick recovery of the hammer after the print cycle.

It is still a further object of the present invention to provide animproved system for actuating a hammer which has a high speedcharacteristic.

It is still another object of the present invention to provide animproved inertia impulse system for imparting energy to a print hammerwhich is extremely accurate at high printing speeds.

It is still a further object of the present invention to provide animproved print hammer actuating mechanism which is inexpensive tomanufacture, simple to incorporate and accurate in use.

Further objects, features and advantages of this invention will becomeapparent from a consideration of the following description, the appendedclaims and the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top view of a writing unitincorporating the features of the present invention;

conventional type which includes a platen 12 adapted to be driven by aline advance stepping motor 14 connected to the platen 12 by means of aline advance belt 16. The belt 16 is driven by the motor through a firstpulley l8 and is connected to the platen by means of a second pulley 20.The motor 14 is of the stepping type which is advanced in response to apulse being fed thereto,. the timing of the pulse being more fullydescribed in conjunction with the description of FIG. 6. Paper is fed tothe platen mechanism from a paper storage bin 24 adapted to receive aplurality of continuous sheets of paper 26, the paper being fed over afirst guide roller 28, under a second guide roller 30, and across thetopof the platen 12. Thus, a succession of pulses being fed to the steppingmotor 14 will advance the paper through the machine in a series ofincremental steps which are related to the spacing between the lines ofprint on the paper.

Relative horizontal movement between the print mechanism, to bedescribed in conjunction with FIGS. 3 to 5, and the paper on the platenis accomplished by means of a character advance assembly 34 whichincludes a horizontal character advance stepping motor 36, a belt 38which is driven by the stepping motor 36 and a drive mechanism(not'shown) which is attached to a print disc assembly 40. The steppingmotor is fed successive pulses in response to each individual printingor spacing operation to advance the print mechanism 40 relative to theplaten 12 in a step-bystep motion. It is to be understood that this inonly one form of print mechanism and other print mechanisms may beutilized such as the type of machine which includes an assembly foradvancing the platen relative to the print assembly 40. The input to thesystem may be provided by means of a keyboard 46 or by electricallyfeeding signals to an input circuit (not shown) within the unit 10.Also, the unit is mounted on a stand which includes a main pedestal 48and a plurality of feet elements 50.

Referring now to FIG. 3, there is illustrated an exploded perspectiveview schematically illustrating a hammer drive mechanism in accordancewith the present invention. Particularly, the print mechanism 40includes a print disc 50 having a plurality of individual fingers 52formed around the periphery of a central hub portion of the disc, theindividual fingers being adapted to carry the characters to be printedon a circumferential outer end of each finger.

A hammer element 56 is mounted adjacent the disc 50 in position tostrike the ends of the fingers 52 and is actuated in response to acontrol system which senses when the selected character finger 52 isproperly positioned under the hammer or will be properly positionedunder the hammer when the hammer strikes the disc 50. In the preferredembodiment, the hammer is actuat'ed through an inertia assembly 60 whichis mounted on a shaft 62 driven from an induction motor 64 through aclutch assembly 66. The induction motor 64 is constantly running in adirection indicated by the arrow on a pulley member 68, the motor64being coupled to the clutch member 66 by means of the pulley 68, a belt70 and a second pulley member 72. The clutchassembly 66 is preferably ofthe magnetic particle type which is energized to engage or couple themotor 64 to the shaft 62 when the assembly is not in a print cycle. Whenthe selected character is to be printed, the clutch 66 is deenergized todecouple the shaft 62 from the motor and a brake assembly 76 isenergized to stop the shaft member 62 at the selected point. The energyto drive the hammer 56 and the disc 50 is transferred from the shaft 62by means of the drive assembly 60 during the non-printing portion ofdirection indicated. The inertia gear 80 is directly coupled to thehammer member by means of-a pin 84 so that the motion of the inertiamember 84 relative to the gear 78, when the print portion of the cycleis initiated, is imparted to the hammer 56. The hammer 56 is rotatablymounted relative to the shaft 62 to permit the hammer 56. to have anangular movement relative to the shaft 62 during the print portion ofthe cycle.

The disc member 50 is driven by a right angle drive which includes afirst bevel gear member 86 fixedly mounted directly on the shaft 62 forrotation therewith and a second bevel gear element 88 which is mountedon the disc 50. Thus, the rotation of the shaft 62 is imparted to thedisc 50 by means of the coupling between the bevel gears 86, 88, and thedisc 50 is synchronously coupled to the rotation of the shaft 62.

The position of the disc relative to a fixed position is sensed by meansof a sensing element 90 which may take any form. For example, a magneticelement may be positioned to sense the passage of the fingers 52 pastthe face of the sensing element 90 and generates a series of pulses inresponse to the number of fingers which pass element 90. These pulsesare fed to a comparator circuit 94 which compares the count of thepulses generated in accordance with the relative positions of theselected character with respect to a fixed position on the disc, thissignal being compared to the selected character as fed to the comparatorcircuit by means of an input conductor 96. Also, a ready signal isprovided the comparator 94 by means of an input conductor 98. Whencoincidence occurs between the selected character and the sensedcharacter, a pulse is generated on an output conductor 100 which causesdeenergization of the clutch 66 and energization of the brake 76 bymeans of conductors 102, 104.

The output signal from the comparator circuit also supplies a pulsetothe timer circuit by means of a conductor 112, the timer circuit beingadapted to provide output pulses to advance the character stepping motorconnected to conductor 114.

Referring now to FIG. 4, there are illustrated further details of thesystem of the present invention. As was discussed in conjunction withFIG. 3, the shaft 62 directly drives the gear 78, the gear78 in turndriving the planetary gear 80 which is directly coupled to the hammer 56by means of the pin84. The hammer is adapted to strike a characterembossed bead disposed between the struck portion of the disc 50 and thepaper supported on the platen 12. A suitable resilient elementl22 isdisposed between a surface 124 of the hammer and a mounting member 126to simulate thicknesses of paper. In this way the striking force of thehammer against the paper is controlled to provide a uniform strikingforce irrespective of the number of sheets of paper supported on theplaten 12.

Also, an adjustable pin member 128 is provided at one end of the hammer.to adjustthe back or rest 'position of the hammer 56 during thenon-print portion of the cycle. It will be noted, with the rotation asindicated in FIGS. 3 and 4 that the planetary gear tends to pull thehammer 56 away from the paper and platen 12. When the shaft 62 isstopped, the inertia of the gear 80, due to the rotation in thedirection indicated, will cause the hammer 56 to rotate about the shaft62 and strike the disc 50. In this way the character embossed on portion120 is printed on the paper supported on platen 12.

FIGS. 4 and 5 also illustrate the details of the right angle driveutilized to impart synchronous rotary motion to the disc 50 from therotation of the shaft 62. As was stated above, the shaft 62 mounts abevel gear 86, the gear 86 being in mating engagement with'a secondbevel gear 84. Thus, the rotary motion of the shaft 62 is imparted to asecond shaft 130 but at right angles thereto. The gear 84 includes anecked down portion which non-rotatably supports the disc 50 and asupport member 132 on which the disc member 50 is mounted. The supportmember 132 and disc 50 are non-rotatably mounted on thegear 84, which inturn is non-rotatably mounted relative to the shaft 130. The shaft 130is rotatably supported by means of a pair of roller bearing assemblies136, 138, which, in addition to taking up any radial forces on the shaft130, also supply thrust resisting forces by means of a washer mounted atthe end thereof.

FIG. 5 particularly illustrates a rotary mounting assembly for providingradial support for the rotating shaft 62. The assembly includes an outerhousing 152 which mounts a further pair of bearing assemblies 154, 156.The housing 152 is supported on the main character printing unit.

With the system of the present invention, the printing disc is driven bythe shaft 62 at a speed which is greater than that allowable for safeno-smear printing. However, the system is caused to decelerate by thedisengagement of the clutch member 66 and the engagement of the brake76, particularly causing the deceleration of the print disc 50. Also,during this deceleration period, the inertia of the planetary gear 80will cause a reverse momentum in the gears to drive the hammer 56 on tothe character printing disc. The reacceleration of the system thencauses the retraction of the hammer away from the character printingdisc.

FIG. 6 illustrates a typical speed versus time curve for the system ofthe present invention, and particularly for the disc member 50. It isseen that during the idle portion of the cycle, the speed of the discexceeds the safe level for no-smear printing. Upon the energization ofthe brake and deenergization of the clutch, the system, with a Ipredetermined lag, will start to decelerate to a point below the safeprinting level. At this time, the hammer strikes the character printingdisc at the print point illustrated in FIG. 6, to cause the character tobe printed on the paper supported by platen 12. The graph of FIG. 6 alsoillustrates a timing circuit multivibrator pulse which is energized inresponse to the start of a print cycle. Simultaneously with the printingof the character, the multivibrator circuit times out to reenergize theclutch and deenergize the brake, causing the system to reaccelerate tothe idle level. Also, at the trailing edge of the multivibrator pulse,the print unit advance pulse is generated by the timing circuit to stepthe character advance stepping motor.

While it will be apparent that the preferred embodiment of the inventiondisclosed is well calculated to fulfill the objects above stated, itwill be appreciated that the invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the subjoined claims.

What is claimed is:

1. In a character recording unit having a character recording andnonrecording cycle, and a character recording mechanism including amovable recording member, and energy storing and delivering system forimparting energy to the recording mechanism during the recording cycleof the character recording unit, the improvement comprising means forimparting stored rotary inertia energy to the movable recording memberby a direct connection between the movable recording member and theinertia storage means including rotary inertia storage means supportedby the movable member of the recording mechanism for movement therewithboth during the non-recording and recording cycles, motive meansconnected to said inertia storage means for rotating the storage meansduring the nonrecording cycle, and delivering means for imparting thestored rotary inertia energy to the recording mechanism through theconnection between the movable member and the rotary inertia storagemeans during the print cycle.

2. The improvement of claim 1 wherein the character recording mechanismis a print mechanism including a print and non-print cycle and saidmovable recording member includes a hammer.

3. The improvement of claim 1 wherein said delivery means includes arotatable element driven by said motive means, said element beingcoupled in driving engagement with said storage means at least duringthe nonrecording cycle.

4. The improvement of claim 3 wherein said motive means includes arotating motor, said motor being energized during both the recording andnonrecording cycles.

5. The improvement of claim 1 wherein said motive means includes arotating motor, said motor being energized during both the recording andnonrecording cycles.

6. The improvement of claim 5 wherein said motive means includes a shaftand a second gear nonrotatably mounted on said shaft, said motor beingcoupled to said shaft by a clutch.

7. The improvement of claim 6 wherein said rotary inertia storage meansincludes a first gear and said delivery means includes a brakeoperatively coupled to said shaft, said brake being energized and saidclutch disengaged during said print cycle.

8. The improvement of claim 7 wherein said second gear is deceleratedduring the cycle by said brake and said first gear element rolls on theperiphery of said second gear element whereby the axis of rotation ofsaid first gear at least partially orbits the axis of rotation of saidsecond gear in a first direction to advance the print mechanism.

9. The improvement of claim 8 wherein said second gear is accelerated atthe end of said print cycle by said motor and said clutch and said firstgear element rolls on the periphery of said second gear element wherebysaid first gear axis orbits said second gear axis in an oppositedirection to said first direction to retract the print mechanism.

10. The improvement of claim 1 wherein the rotary inertia storage meansis mounted on the movable recording member for movement therewith.

11. The improvement of claim 10 wherein the movable recording memberis-pivotally mounted for pivotal movement of the movable recordingmember and the rotary inertia storage means, the stored rotary inertiabeing at least in part transferred to the pivotally mounted movablerecording member by pivotal movement thereof to effect recording duringthe recording cycle.

12. The improvement of claim 11 wherein the movable recording memberincludes a print hammer and wherein the character recording mechanism isa print mechanism including a print and non-print cycle.

13. The improvement of claim 11 wherein said motive means includes arotating motor, said motor being energized during both the recording andnonrecording cycles and said first and second direct drive means includefirst and second gear elements, respectively.

14. The improvement of claim 13, wherein said motive means includes ashaft and said second gear element is non-rotatably mounted on saidshaft, said motor being coupled to said shaft by a clutch.

15. The improvement of claim 14, wherein said delivery means includes abrake operatively coupled to said shaft, said brake being energized andsaid clutch disengaged during said print cycle.

16. The improvement of claim 15, wherein said second gear is deceleratedduring the cycle by said brake and said first gear element rolls on theperiphery of said second gear element whereby the axis of rotation ofsaid first gear at least partially orbits the axis of rotation of saidsecond gear in a first direction to advance the print mechanism.

17. The improvement of claim 16, wherein said second gear is acceleratedat the end of said print cycle by said motor and said clutch and saidfirst gear element rolls on the periphery of said second gear elementwhereby said first gear axis orbits said second gear axis in an oppositedirection to said first direction to retract the print mechanism. I

1. In a character recording unit having a character recording andnonrecording cycle, and a character recording mechanism including amovable recording member, and energy storing and delivering system forimparting energy to the recording mechanism during the recording cycleof the character recording unit, the improvement comprising means forimparting stored rotary inertia energy to the movable recording memberby a direct connection between the movable recording member and theinertia storage means including rotary inertia storage means supportedby the movable member of the recording mechanism for movement therewithboth during the non-recording and recording cycles, motive meansconnected to said inertia storage means for rotating the storage meansduring the nonrecording cycle, and delivering means for imparting thestored rotary inertia energy to the recording mechanism through theconnection between the movable member and the rotary inertia storagemeans during the print cycle.
 2. The improvement of claim 1 wherein thecharacter recording mechanism is a print mechanism including a print andnon-print cycle and said movable recording member includes a hammer. 3.The improvement of claim 1 wherein said delivery means includes arotatable element driven by said motive means, said element beingcoupled in driving engagement with said storage means at least duringthe nonrecording cycle.
 4. The improvement of claim 3 wherein saidmotive means includes a rotating motor, said motor being energizedduring both the recording and nonrecording cycles.
 5. The improvement ofclaim 1 wherein said motive means includes a rotating motor, said motorbeing energized during both the recording and nonrecording cycles. 6.The improvement of claim 5 wherein said motive means includes a shaftand a second gear nonrotatably mounted on said shaft, said motor beingcoupled to said shaft by a clutch.
 7. The improvement of claim 6 whereinsaid rotary inertia storage means includes a first gear and saiddelivery means includes a brake operatively coupled to said shaft, saidbrake being energized and said clutch disengaged during said printcycle.
 8. The improvement of claim 7 wherein said second gear isdecelerated during the cycle by said brake and said first gear elementrolls on the periphery of said second gear element whereby the axis ofrotation of said first gear at least partially orbits the axis ofrotation of said second gear in a first direction to advance the printmechanism.
 9. The improvement of claim 8 wherein said second gear isaccelerated at the end of said print cycle by said motor and said clutchand said first gear element rolls on the periphery of said second gearelement whereby said first gear axis orbits said second gear axis in anopposite direction to said first direction to retract the printmechanism.
 10. The improvement of claim 1 wherein the rotary inertiastorage means is mounted on the movable recording member for movementtherewith.
 11. The improvement of claim 10 wherein the movable recordingmember is pivotally mounted for pivotal movement of the movablerecording member and the rotary inertia storage means, the stored rotaryinertia being at least in part transferred to the pivotally mountedmovable recording member by pivotal movement thereof to effect recordingduring the recording cycle.
 12. The improvement of claim 11 wherein themovable recording member includes a print hammer and wherein thecharacter recording mechanism is a print mechanism including a print andnon-print cycle.
 13. The improvement of claim 11 wherein said motivemeans includes a rotating motor, said motor being energized during boththe recording and nonrecording cycles and said first and second directdrive means include first and second gear elements, respectively. 14.The improvement of claim 13, wherein said motive means includes a shaftand said second gear element is non-rotatably mounted on said shaft,said motor being coupled to said shaft by a clutch.
 15. The improvementof claim 14, wheRein said delivery means includes a brake operativelycoupled to said shaft, said brake being energized and said clutchdisengaged during said print cycle.
 16. The improvement of claim 15,wherein said second gear is decelerated during the cycle by said brakeand said first gear element rolls on the periphery of said second gearelement whereby the axis of rotation of said first gear at leastpartially orbits the axis of rotation of said second gear in a firstdirection to advance the print mechanism.
 17. The improvement of claim16, wherein said second gear is accelerated at the end of said printcycle by said motor and said clutch and said first gear element rolls onthe periphery of said second gear element whereby said first gear axisorbits said second gear axis in an opposite direction to said firstdirection to retract the print mechanism.